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Initial Assessment of Graphite Precipitates in Vermicular Cast Iron in the As-Cast State and after Thermal Treatments

Soiński M. S., Jakubus Aneta, Borowiecki B., Mierzwa P.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 4

131--136

EN

The purpose of the work was to determine the morphology of graphite that occurs in vermicular cast iron, both in the as-cast state and after heat treatment including austenitization (held at a temperature of 890°C or 960°C for 90 or 150 min) and isothermal quenching (i.e. austempering, at a temperature of 290°C or 390°C for 90 or 150 min). In this case, the aim here was to investigate whether the heat treatment performed, in addition to the undisputed influence of the cast iron matrix on the formation of austenite and ferrite, also affects the morphology of the vermicular graphite precipitates and to what extent. The investigations were carried out for the specimens cut from test coupons cast in the shape of an inverted U letter (type IIb according to the applicable standard); they were taken from the 25mm thick walls of their test parts. The morphology of graphite precipitates in cast iron was investigated using a Metaplan 2 metallographic microscope and a Quantimet 570 Color image analyzer. The shape factor F was calculated as the quotient of the area of given graphite precipitation and the square of its perimeter. The degree of vermicularization of graphite was determined as the ratio of the sum of the graphite surface and precipitates with F <0.05 to the total area occupied by all the precipitations of the graphite surface. The examinations performed revealed that all the heat-treated samples made of vermicular graphite exhibited the lower degree of vermicularization of the graphite compared to the corresponding samples in the as-cast state (the structure contains a greater fraction of the nodular or nearly nodular precipitates). Heat treatment also caused a reduction in the average size of graphite precipitates, which was about 225μm2 for the as-cast state, and dropped to approximately 170-200 μm2 after the austenitization and austempering processes.

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Zastosowanie wysokich cisnień w przemyśle mięsnym

Pietrzak D., Mroczek J.

Przemysł Spożywczy

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2002

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T. 56, nr 10

38-41

PL

Wśród nowoczesnych sposobów utrwalania żywności, których głównym celem jest ograniczenie rozwoju bądź eliminacja drobnoustrojów, coraz większym powodzeniem cieszy się metoda wysokociśnieniowa określana w skrócie jako UHP (Ultra High Pressure). W ostatnich latach prowadzone są intensywne badania nad praktycznym zastosowaniem wysokich ciśnień w celu poprawy jakości i trwałości przetworów rybnych, mięsnych, mlecznych, owocowych i warzywnych. W artykule przedstawiono możliwości wykorzystania wysokich ciśnień w przemyśle mięsnym oraz ich wpływ na jakość gotowych produktów.

EN

Ultra high pressure processing (UHP) in one of new very promising technologies for the preservation of meat products (the inactivation or reducing the number of microorganisms). Nowadays this technology is getting more and more popular. In the last years many experiments were carried out considering the UHP industrial application (e.g. in the meat, fish, dairy and juice sector). The aim of all the studies was to improve the quality of the product. In this paper the results of the studies on the effect of UHP on quality of meat products and the possible applications of that technology in meat industry were reviewed.

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Influence of the preparation of carbonaceous supports impregnated with a copper nitrate solution on the catalytic oxidation of methanol, ethanol and isopropanol.

Azambre B., Heintz O., Krzton A., Zawadzki J., Weber J.V.

Prace Naukowe Instytutu Chemii i Technologii Nafty i Węgla Politechniki Wrocławskiej. Konferencje

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1999

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Vol. 9, nr 56

121-127

EN

Microcristalline cellulose was thermally treated in order to obtain a carbonaceous support. Thermolyses at 450 C were done under different conditions and the effect of some thermal parameters was evaluated in respect with the final porosity of the sample and the yield of solid residue at the end of the carbonization processes. Pretreatments under air or N2 at 250 C were found to be unable to further increase the char yield but very efficient in order to expand the porosity of the sample. The carbonized residues were oxidized in air in a TG oven under different temperature conditions and characterized by DRIFTS and XPS. Analyses of functional group by DRIFTS and XPS seem to show the progressive conversion of carboxyles to anhydrides during the oxidation. The diferent supperts were then impregnated with a copper nitrate solution. After a thermal treatment under N2 or H2, some of them were found to be very efficient fot the catalytic oxidation of alcohols. The effect of both functional groups, copper oxidation state and copper loading was noticed onto conversion yields and degradation pathways.